Electrolysis Flashcards
What is electrolysis?
splitting up a compound using electricity to separate them into their own elements
What is the electrolyte?
liquid/solution that contains an ionic compound and the ions are free to move within it
if the compound is soluble it can be dissolved in water to make the electrolyte
if the compound is insoluble it can be melted to become a molten liquid where the ions are free to move around to make the electrolyte.
What is the electrode?
solid conductors of electricity (metal/carbon)
What is the purpose of the wire in electrolysis?
so that the electrons can flow through
What is the purpose of the power supply in electrolysis?
to drive the flow of electrons
Describe the process of electrolysis
the anions are attracted to the anode and get discharged and become a neutral atoms which allows them to form their own compounds
the cations are attracted to the cathode and get discharged and become a neutral atom which allows them to form their own compounds
the electrons from the anion that is lost/oxidised are transferred to the anode and transported to the wire to reach the cathode and reduce the positive ions, this whole process is powered by the battery.
At both electrodes are the ions being oxidised or reduced?
at the anode the ions are being oxidised
at the cathode the ions are being reduced
Describe the electrolysis of lead (ii) bromide
. reduced
Pb2+ + 2e- -> Pb
oxidised
2Br- -> Br2 + 2e-
lead (ii) bromide is insoluble therefore it must be heated to become molten.
the bromine ions go to the anode and lose electors and they transfer to the lead
the bromine becomes neutral and forms bromide and bond together
the lead ions go to the cathode and gains 2 electrons and then sinks to the bottom
Why is carbon used as an electrode?
because it is inert and very unreactive so it wont affect the reaction
Why must the electrolyte be molten/dissolved?
so they can move freely and go to their respective electrode
What are the rules for electrolysis??
if there are 2 ions going to the cathode, the least reaction element will be discharged
at the anode if a halide is present, they get discharged. if not, then the hydroxide will.
What ions are in aqueous solutions?
they have water so H+ and -OH ions
Why don’t covalent compounds conduct electricity?
they are neutral and don’t have charged particles to move and carry charge
Describe the electrolysis of NaCl
NaCl + H20
ions: Na+ Cl- H+ -OH
cathode: hydrogen is reduced
anode: chlorine is oxidised
Describe the electrolysis of CuSO4
ions: Cu2+, SO42-, H+, -OH
cathode: copper is reduced
anode: hydroxide is oxidised
Describe the electrolysis of H2SO4
ions: H+, SO42-, H+, -OH
cathode: hydrogen is reduced
anode: hydroxide oxidised
